I have a 1999 Chevy Tahoe with the tow package. It's rated to tow up to
6,500 pounds. I usually do not tow but I periodically tow a 3,000 pound
boat or a 5,000 pound travel trailer (not both at once, of course!). It had
a single external transmission cooler until a couple of months ago.
Long story made short: Transmission shop recommended and installed a second
auxiliary transmission cooler -- for a total of three coolers including the
one inside the main radiator -- because they suspected excessive
transmission heating. A couple weeks later while towing the travel trailer
the transmission failed (as in only neutral "worked"), and a lot of
transmission fluid was found in the engine coolant overflow reservoir.
Tranny shop bypassed the transmission cooler in the main radiator since it
appeared to be leaking. So now I am not using the transmission cooler part
of the main radiator and am instead using the TWO external transmission
coolers. Transmission shop said I'm good to go now and suggested I stay
away from using the main radiator's transmission cooler because a leak can
ruin the transmission (as it did!). By using ONLY external coolers I'll
never have to worry about THAT happening ever again, they said.
I took it to a radiator shop for a second opinion from their perspective.
They said the transmission cooler in the main radiator is needed if I will
ever drive in a cold climate because that is the only "cooler" that will
the transmission fluid when needed. They also said that a
leak in the main cooler is extremely rare, so I really shouldn't worry about
that happening again once the existing main cooler is replaced.
So now I'm wondering what to do. My options are:
1. Leave it the way it is. Use just the two auxiliary transmission coolers
and bypass the transmission cooler in the main radiator.
2. Replace the transmission cooler component of the main radiator and put
it back in series with the two aux coolers. With this I'll have three
tranny coolers as well as the risk of a future leak costing me another
$2,500 in transmission repairs.
3. Same as #2 but disconnect one of the aux coolers (one person suggested
to me that three coolers is not a good idea but I don't know why).
What is your opinion? I live in a mild climate (Portland, Oregon) where it
is usually above freezing and rarely more than a few degrees below freezing,
but I sometimes do drive in the winter-time to much colder places (without
I have a second question which I'll post separately.